Transnationals' growing importance within world economy has become an extremely controversial topic. Appreciated by some, disapproved by others, these giant firms are certainly reality in nowadays economy and they are the most important economic agents all over the world. Companies of this kind have reached so much expansion that they have somehow lost their national feature. For these firms competition is no longer national, but international, against foreign companies with the same profile, to cover large segments of the global market. Transnationals are fundamental in competition's globalization. Transnational manufacturing has inserted the global competition within national markets, so that many firms are forced to manufacture at the international border of efficiency or get out of business. Transnationals have developed over the last decades, as they have worked on their competitive advantages at international level. These advantages emerge from scale economies, higher management techniques and/or world sales networks. The rapid changes brought about by globalization generate new huge opportunities for those able to find the answers that suit the new conditions, but also imply new risks to those who cannot adapt.